The Linux operating system that was created as a hobby by a young student, Linus Torvalds, at the University of Helsinki in Finland. Linus, interested in the UNIX clone operating system Minix, wanted to create an expanded version of Minix with more capabilities. He began his work in 1991 when he released version .002 and invited programmers to participate in his project. Version 1.0 was released in 1994 and development continues.

Linux uses the GNU General Public License (GPL) and its source code is free for use and available to everyone. Linux distributions, CD-ROMs with the Linux kernel and various other software ready for installation, do not have to be non-commercial, but the Linux source code must remain available. Making source code available is known as open source.

The word "Linux" is properly pronounced using a Swedish accent, making it difficult to pronounce in North America. It is most often pronounced with a short "i" and with the first syllable stressed, as in LIH-nicks, but it is sometimes pronounced LYE-nicks (the Anglicized "Linus' UNIX") or LEE-nucks.

Strictly speaking, Linux refers to the operating system that starts and manages other programs and provides access to system resources. The various open source shells, compilers, standard libraries and commands are a part of another project call GNU. The GNU project was started by the Free Software Foundation (FSF) as an attempt to create a free version of UNIX. The main Linux C compiler, gcc, is part of the GNU project.

The Linux kernel was designed to be hardware independent. That is, although Linux is often associated with Intel-based x86 servers, it will run on a variety of other hardware platforms as well, including Apple, Alpha, Sun and SGI computers.

Other common software, like the X Windows desktop or Novell's Mono .Net support, are technically not a part of Linux but are often included as part of a Linux distribution.

Besides Linux, there are other open source operating systems available, notably GNU Hurd and FreeBSD. However, Linux is the open source operating system with the largest market share.